Method for manufacturing medical device having embedded traces and formed electrodes

ABSTRACT

Disclosed is a method of manufacturing a catheter or lead having electrically conductive traces and external electrical contacts. Each trace may be in electrical connection with one or more external electrical contacts. More specifically, each trace is typically electrically connected to a single contact. The traces and contacts may assist in diagnosis and/or detection of bio-electric signals emitted by organs, and may transmit such signals to a connector or diagnostic device affixed to the catheter. The external contacts may detect bioelectric energy or may deliver electrical energy to a target site.

This application is related to U.S. patent application Ser. No.10/668,843, filed Sep. 22, 2003, entitled “Medical Device HavingIntegral Traces and Formed Electrodes.”

FIELD OF THE INVENTION

The invention relates generally to the field of medical instruments, andmore particularly to a medical instrument for introduction into a bodyand having arbitrarily-shaped electrically conductive surfaces formedthereon.

BACKGROUND ART

Catheters have been in use for medical procedures for many years. Amongother uses, catheters can be used for medical procedures to examine,diagnose, and/or treat tissue while positioned at a specific locationwithin the body otherwise inaccessible without more invasive procedures.For example, one procedure (often referred to as “catheter ablation”)utilizes a catheter to convey electrical energy to a selected locationwithin the human heart to necrotize cardiac tissue. This procedure isoften colloquially referred to as “ablation” of cardiac tissue.

Another procedure, oftentimes referred to as “mapping,” utilizes acatheter with sensing electrodes to monitor various forms of electricalactivity in the human body. Various organs, including the heart andbrain, may be mapped by a catheter having appropriate diagnosticfunctions. Mapping may be thought of as the opposite of ablation, insome respects. Specifically, a mapping catheter detects bioelectricimpulses generated by the tissue in question and relays thesebioelectric impulses to a diagnostic machine operably attached to thecatheter. Accordingly, instead of transmitting energy to tissue, themapping catheter transmits energy from tissue.

Regardless of the direction of energy transmission, present cathetersgenerally mechanically mount the energy delivery media, such aselectrodes, to the catheter surface. Further, the transmission media,typically one or more wires, is generally strung through an opening inthe center of the catheter, and is not attached to the catheter save atthe connection point with the energy delivery medium. Accordingly, asthe catheter is steered, bent, or moved, stress may be applied to theinternal wires. Additionally, when medical instruments are inserted intothe catheter interior, the surgeon must exercise some degree of care toensure the instruments do not interfere with the diagnostic functions ofthe catheter or, possibly, damage the wires.

Further, many diagnostic and energy delivery catheters have multiplewires running to a variety of diagnostic or energy delivery sites. Atthe catheter's proximal end, these wires often simply terminate withlittle or no identification separating one wire from the next, makingattaching a wire to the appropriate connector pin of a medical devicedifficult.

Apparatus leads often suffer from similar problems. Leads may be used todeliver energy to tissue, typically in order to regulate tissuecontraction through timed pulses of electricity. Such regulation mayoccur, for example, by a pacemaker. Further, in many neurosurgicalapplications, leads or catheters may be used to map an area of the brainby electrical measurement, as described above, or by electricallystimulating a portion of the brain to elicit a response. Energy may befurther delivered through a lead to ablate tissue and alleviateirregular symptoms plaguing the tissue. In any of these energy-deliveryapplications, however, the problems identified above typically stillexist.

Accordingly, there is a need for an improved medical device capable oftransmitting electrical energy across its length either to or from atarget site.

SUMMARY OF INVENTION

Generally, one embodiment of the present invention takes the form of acatheter having electrically conductive traces and external electricalcontacts. Each trace may be in electrical connection with one or moreexternal electrical contacts. More specifically, each trace is typicallyelectrically connected to a single contact. The traces and contacts mayassist in diagnosis and/or detection of bio-electrical signals emittedby organs, and may transmit such signals to a connector or diagnosticdevice affixed to the catheter.

In another embodiment, a catheter may be provided with energy-conductivetraces or wires and external energy emission sites capable of deliveringelectrical or thermal energy to a target site within or on a patient'sbody. The conductive wires may be braided, channeled, run through, orformed within the catheter's wall structure. The wires are generallyflexible and permit bending and movement of the catheter as necessary.Where electrical energy is channeled through the wires or traces,electrodes are generally formed on the outside of the catheter. If asignificant quantity of energy must be delivered, multiple traces may beconnected to a single electrode, or wires may be used in lieu of asingle trace.

Yet another embodiment takes the form of a lead having integrated,electrically-conductive traces and electrodes formed along its exterior.The distal portion of the lead may be placed within a patient's body andthe proximal end connected to a pacemaker or other medical device. Thetraces and electrodes facilitate monitoring the patient's condition and,if appropriate for the attached device, regulating tissue contraction bydelivering timed pulses of electrical energy along the trace, throughthe electrode, and to the tissue. Where a significant quantity of energymust be delivered, multiple traces or wires may be used in lieu of asingle trace.

In yet another embodiment of the present invention, a medical device maybe provided with one or more arbitrarily-shaped electrodes on itssurface, for example at the device tip. These arbitrarily-shapedelectrodes operate in either a diagnostic or energy-delivering mode, asnecessary. The arbitrarily-shaped electrodes may obtain improvedinformation on electrical signal directional propagation when recordingtissue responses to electrical energy, and may also improve accuracywhen ablating tissue.

Generally, one method for manufacturing a device with arbitrarily-shapedelectrodes may be forming a device body from a nonconductive material,determining a shape for the electrode, forming the electrode from aconductive, biocompatible material in the determined shape, attaching anelectrically conductive element (such as a trace or wire) to theelectrode, affixing the electrically conductive element and theelectrode to a section of the device, overmolding the electrode with anovermold material, and removing a portion of the overmold material abovethe electrode sufficient to expose the electrode. An arbitrarily-shapedelectrode may also be formed by electrodepositing or sputteringconductive material on or in a depression or hollow formed on the devicebody, and may be connected to a conductive trace or wire by a via.

SUMMARY OF DRAWINGS

FIG. 1 depicts an isometric, partially-exploded view of a catheterhaving traces and electrodes integrated therein, in accordance with afirst embodiment of the present invention.

FIG. 2 depicts a fragmentary, isometric, partially-exploded view of asolid-core catheter having integrated traces and electrodes.

FIG. 3 depicts a partially-exploded side view of the catheter of FIG. 1.

FIG. 4 depicts a fragmentary, cross-sectional view taken along line A-Aof FIG. 3.

FIG. 5 depicts a fragmentary, cross-sectional view taken along line B-Bof FIG. 3 and also including an optional adapter outer jacket.

FIG. 6 depicts an isometric, partially-exploded view of a singlecatheter having integrated traces and electrodes and multiple catheterlayers, namely an outer jacket, an outer tube, and an inner tube.

FIG. 7 depicts a partially-exploded side view of the catheter of FIG. 6.

FIG. 8 depicts a fragmentary, cross-sectional view of the catheter ofFIGS. 6 and 7, taken along line C-C of FIG. 7.

FIG. 9 depicts a fragmentary, cross-sectional view of the catheter ofFIGS. 6 and 7, taken along line D-D of FIG. 7.

FIG. 10 depicts an isometric view of an adapter having a planar end.

FIG. 11 depicts an isometric view of an cylindrical embodiment of anadapter.

FIG. 12 depicts the cylindrical adapter of FIG. 11, as viewed from themating end.

FIG. 13 depicts a cross-sectional view of the cylindrical adapter ofFIGS. 11 and 12, taken along line E-E of FIG. 12.

FIG. 14 depicts an isometric, partially-exploded view of a catheterhaving embedded wires in lieu of traces.

FIG. 15 depicts a partially-exploded side view of the catheter of FIG.14.

FIG. 16 depicts a fragmentary, cross-sectional view of the catheter ofFIGS. 14 and 15, taken along line F-F of FIG. 15.

FIG. 17 depicts a fragmentary, cross-sectional view of the catheter ofFIGS. 14 and 15, taken along line G-G of FIG. 15, and with the adapterinserted into the catheter body.

FIG. 18 a is a flowchart depicting an exemplary method of manufacturingan embodiment of the present invention.

FIG. 18 b is a flowchart depicting an exemplary method of overmolding acatheter or lead shaft containing embedded traces or wires.

FIG. 19 depicts an isometric, partially-exploded view of a catheterhaving arbitrarily shaped electrodes.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Generally, one embodiment of the present invention takes the form of amedical device, such as a catheter or lead, having integrally formedelectrodes and conductive elements. In this context, “integrally formed”refers to the fact that the electrodes and conductive elements aregenerally not mechanically affixed to the device, but instead are bondedthereto, formed on, or co-extruded with the device.

Exemplary medical devices include catheters and leads. As used herein,references to either a “catheter” or a “lead” are each intended toembrace the other term, unless specifically stated otherwise.

The medical device may conduct electricity generated by an apparatusattached to its proximal end to a contact site on its distal end (or toany point therebetween) by means of the integrally formed conductiveelements. Energy may be delivered to the device's surface byelectrically connecting a conductive element to an electrode. Generally,exemplary electrically conductive elements include metallic traces andwires. Energy may be conducted, for example, to necrotize or selectivelydamage tissue (also referred to as “ablation”).

In addition to delivering energy to a contact site, a device embodyingthe present invention may also be used for diagnostic purposes. Theelectrodes or other contact sites formed along the exterior of thedevice may monitor bioelectric signals generated by tissue and transmitthese signals along the previously mentioned traces or wires to amonitoring apparatus attached to the device's proximal end. Thesedelivery sites may be located at the device's distal end or anywherealong its length. Alternative embodiments may include thermistors orthermocouples capable of monitoring temperature.

A portion of the device may include a braided material to impartadditional stiffness and/or structural strength. For example, a portionof the device's exterior may have braids formed therein, while aseparate portion of the device may lack such braids in order to permitmore ready flexing. The braids may form a cross-hatch pattern tofacilitate stiffness. Such braids may be made from a metal wire or anonconductive fiber. One example of a nonconductive fiber suitable foruse as a stiffening braid is Vectran. Vectran, or another nonconductivefiber, is typically used in place of metal wire if a via passes throughthe braided portion of the shaft and/or an electrode is formed on theouter surface of the shaft above the braided material. By employing anonconductive fiber, the electrical signal along the via is not subjectto interference, as it may be if a metal wire is used instead.

Additionally, the device may include an adapter. The adapter facilitatesconnection between the device and a diagnostic or energy-generatingapparatus. The adapter generally includes embedded, conductive adaptertraces that may connect the traces or wires inside the device toapparatus leads. The adapter shape (as well as the shape of the portionof the adapter mating with the apparatus) may vary. Further, the adaptermay be enclosed within an outer shell or jacket. The jacket may protectthe traces formed on the adapter, and also may include electricalconnections facilitating the connection of a diagnostic or ablativeapparatus to the device.

1. Embodiment of the Invention

FIG. 1 depicts a partially-exploded isometric view of a catheter 100having traces 102 and electrodes 104 integrated therein, in accordancewith an embodiment of the present invention. Generally, the catheter 100includes at least one embedded or integrally formed, electricallyconductive trace 102 or wire electrically connected to at least oneelectrode 104 formed on the outer surface of the catheter. Generally, anelectrode 104 is formed in a depression 126, such that the outer surfaceof the electrode is flush with the catheter's outer surface. Typically,at least a portion of the catheter body is formed of an electricallynonconductive material.

In the view shown in FIG. 1, the catheter tip 106 (including tipelectrode 108) is shown disconnected from the catheter shaft 110 inorder to depict the traces 102, inner layer (in this case, a tube 112),and lumens 116. In operation, the tip 106 is affixed to the catheter100.

As can be seen in FIG. 1, the present embodiment includes two nestedlayers, namely an inner catheter layer (or “tube”) 112 and outercatheter layer (or “jacket”) 114. As used herein, “jacket” typicallyrefers to the outermost concentric layer of the device, while “tube”typically refers to an inner concentric layer. Generally, the term“layer” may refer to a tube 112 or jacket 114.

Generally, the catheter 100 may be made of multiple tubes 112 and/orjackets 114, concentrically nested. For example, the catheter may havetwo tubes, one inside the other, both of which are inside a jacket.Further, the catheter 100 may be made of multiple tubes 112 and/orjackets 114 spaced along the catheter's longitudinal axis. For example,three jackets may be spaced along the length of the catheter, each ofwhich abuts an adjacent jacket. In other words, the catheter shaft 110may be segmented, and may not consist of a single tube 112 or jacket 114running along its entire length.

The tube 112 rests within the jacket 114, and is generally sized so thatthe outer surface of the tube contacts substantially all of the innersurface of the jacket. In other words, no longitudinal void spacegenerally exists between the tube 112 and jacket 114 sidewalls. Voidspaces may exist, however, where vias or passages are deliberatelyformed through a portion of the catheter 100. The tube 112 may be atleast partially hollow (i.e., have one or more lumens 116) to allowincorporation of a steering mechanism, support deformable cathetersegments, support fluid flow for cooling or providing an electricallyconductive path to tissue, or permit passage of a lead or instrumenttherethrough. Alternatively, the tube 112 may have a solid core. FIG. 1depicts a catheter with a partially hollow core (more specifically, witha bi-lumen tube 112), while FIG. 2 depicts a catheter 100 having asolid-core tube 200.

Returning to FIG. 1, electrically conductive traces 102 or wires aretypically formed or placed on an exterior sidewall of the tube 112,while electrodes 104 are formed on the shaft 110 exterior. In oneembodiment of the present invention, traces 102 may be formed on theexterior of the shaft 110. These traces may terminate in an electrodeplaced or formed on the jacket 114 exterior.

Alternatively, traces 102 may be formed on an inner sidewall of thejacket 114, or may be formed on an exterior sidewall of the tube 112, ormay be embedded in either the jacket or tube. In yet another alternativeembodiment, an externally-formed trace 102 may later be covered with alayer of nonconductive material to minimize signal interference.

In embodiments lacking externally-formed traces 102, each tracetypically at least partially underlies an electrode 104. A via (notshown) may be formed from the underside of the electrode extendingthrough the jacket 114 and to a trace 102, thus electrically connectingthe electrode to the trace. This connection permits the trace to passelectrical energy from a medical device affixed to the outside of thecatheter 100 at its proximal end to the electrode 104, or vice versa.The trace may be offset either along the longitudinal or lateral axes ofthe catheter from the electrode, so long as some portion of the traceremains in contact with the electrode.

Further, as shown in FIGS. 1 and 2, the geometry of a trace 102 andelectrode 104 may vary widely. For example, the electrode 104 may befully or partially cylindrical, forming a ring stretching partially orentirely around the circumference of the jacket 114. Regardless ofelectrode 104 shape, the trace 102 typically runs along the longitudinalaxis of the catheter 100 at least to the edge of the electrode, but doesnot generally extend along the entire circumference of the tube 112. Thetrace may also have any cross-sectional shape desired. Accordingly, thelateral and longitudinal cross-sections of both the electrode 104 andtrace 102 may vary, as may the depth or thickness of the trace andelectrode.

In another embodiment, the outer surface of the tube 112 may include atrace 102 formed thereon. The trace extending along the tube's outersidewall may conduct electrical energy from a connected apparatus to theelectrode 104 formed on the outside of the jacket 114 (or anywhere alongthe shaft 110, in embodiments where the jacket only partiallyencapsulates the shaft), and vice versa. In yet another embodiment, theinner surface of the jacket 114 may include a trace 102 formed thereon.In such an embodiment, the outer surface of the tube 112 typically willnot include any traces 102 in order to minimize the possibility ofsignal interference between two adjacent traces (i.e., one on the innersurface of the jacket 114 and one on the outer surface of the adjacenttube 112).

In the present embodiment, each trace 102 typically electricallyconnects to a single electrode 104. In this manner, discrete electricalsignals are communicated between the electrode and any apparatusattached to the proximal end of the trace, minimizing or eliminatingsignal interference or cross-talk. If an apparatus controls or employsmultiple sensory points through a single trace 102, then the trace inquestion may contact multiple electrodes 104.

Although reference has been made to a “trace” 102 above in describingembodiments, in some embodiments a single trace may be insufficient tocarry the current necessary for diagnosis or operation. For example,when the catheter 100 is used to selectively necrotize or remove tissue(collectively referred to as “ablation” of tissue), more current may berequired than a single trace 102 may carry. Accordingly, an alternativeembodiment of the present invention may employ multiple traces 102 orelectrically conductive wires in lieu of a single trace. Thus,throughout this document, the term “trace” should be understood toencompass multiple traces 102 or a wire, except where specificallydisclaimed or such cross-reference renders the embodiment beingdiscussed infeasible. Similarly, references to a “wire” should beunderstood to encompass a trace 102 or traces.

Continuing the discussion of FIG. 1, wire or nonconductive fiber of anysuitable material (generally, “braided material” or “braided wire” 118)may be braided into a tube 112 section or portion of the jacket 114 tostabilize and stiffen the catheter. Alternatively, such braided material118 may be co-extruded with a layer or placed between layers. Generally,this braided wire does not conduct energy during catheter operation, andis not operably connected to a trace 102 or electrode 104. Further, thebraided wire 118 typically is embedded within the jacket 114, ratherthan placed along its surface where it may abrade tissue if insertedwithin a body. The braided wire may or may not be visible to the eyewhen the catheter shaft 110 is viewed. Accordingly, the wire 118 isshown in phantom in FIGS. 1 and 2. If the braid is placed in or along aportion of the device that may result in the braid electricallycontacting a trace 102, via, or electrode 104, a suitable nonconductivematerial may be employed to minimize electrical cross-talk or signalinterference. One such nonconductive material is Vectran.

The present embodiment may also include a connector or adapter structure120. In its most general aspect, the adapter 120 includes oneelectrically conductive adapter trace 122 extension for each trace 102within the catheter 100. The extension 122 mates with, aligns with, orotherwise operably connects to the trace, and extends directly orthrough a suitable electrical connection means to a plug, pin, orconnector portion which, in turn, facilitates an electrical connectionto a medical apparatus, such as a monitoring device. Accordingly, theadapter 120 assists in connecting the electrodes 104 on the catheter 100to a medical device. The adapter is more fully discussed below withrespect to FIG. 10.

The catheter tip 106 may be fabricated from a number of materials ormaterial combinations, depending on the desired function of the catheter100. For example, the catheter tip 106 may include one or moreelectrodes 104, or may be entirely covered by a single tip electrode108, when the catheter is used for diagnostic or ablative purposes.Alternatively, where such functions are unnecessary, the catheter tip106 may be formed from a non-conductive material, such as that used toform the jacket 114 or shaft 110, or may be simply metal-plated with nooperable connection to any trace 102, wire, or electrode 104. Further,if a medical device such as a lead is passed through the catheter 100,the tip 106 may have an opening at its end, regardless of the materialused to construct the tip.

In an alternative embodiment, the tip 106 may be formed of radiopaquematerial to permit detection of the tip during fluoroscopy or relatedprocedures. The radiopaque material may alternatively be bonded to theinside or outside of the catheter 100, along the lumen 116, or may beembedded within the catheter walls. Further, the radiopaque material maybe suspended within a polymer, or may be one or more solid, contiguouspieces of material. For example, the radiopaque material may take theform of fine particles suspended in a polymer tube, or may be a ring ofradiopaque substance bonded to the inner surface of the jacket 114 ortube 112. Exemplary radiopaque materials suitable for use with thepresent invention include metals such as platinum, tungsten, gold, orother metals opaque to x-rays, or polymeric materials designed to bex-ray opaque.

The embodiment may also be provided with temperature sensingcapabilities. For example, a thermistor 124 may be embedded or otherwiseincorporated into the nonconductive jacket 114. The thermistor leads (inthe case of a chip-style thermistor) may be attached to or come incontact with the aforementioned traces 102 in order to accurately conveytemperature readings to an associated medical device at the proximal endof the catheter 100. Thermistors are typically placed in a depression126 in order to keep the outer surface of the thermistor flush with theshaft 110 exterior.

Alternatively, a thermistor 124 may be located beneath or adjacent to anablation electrode 104 in order to measure the electrode temperatureduring ablation. The thermistor may, for example, be placed in adepression 126 in the jacket surface and covered with a relatively thinlayer of nonconductive material to prevent electrical interference. Theelectrode 104 may then rest above the thermistor 124, at least partiallywithin the same depression 126 and connected to a trace 102 other thanthat operably connected to the thermistor. In this manner, thethermistor may measure the operating temperature of the electrodewithout interfering with the electrode's operation.

In yet another alternative embodiment, the thermistor 126 may bereplaced by a thermocouple (not shown). In such an embodiment,thermocouple wires (for example, constantan and copper) may beincorporated into the jacket 114 or tube 112 during manufacture of theappropriate layer, or may be sandwiched between layers. If the wires areincorporated into a layer, they may be co-extruded with the layer. Adepression 126 in the layer above the wires may permit exposure of thewires and formation of a thermocouple junction, as necessary. Again, anelectrode 104 may be placed or formed within the depression 126 and thethermocouple may measure the temperature generated by the electrode toassist, for example, in monitoring tissue temperature experienced duringablation. If necessary, an electrically nonconductive (but heatconductive) layer may separate the thermocouple junction and electrode.Such a layer generally will withstand the temperature generated by theelectrode 104 without deforming, warping, or suffering performanceimpairment.

A catheter 100, such as that of FIG. 1, may also incorporate a steeringmechanism. A directional control mechanism of any type presently usedmay placed inside the catheter's lumen 116. Generally, at the distal endof the catheter 100, the directional control assembly is attached to thecatheter tip 106. A wire or directional guide is affixed to a steeringmechanism located at or outside the proximal end of the catheter. Thecontrol assembly may be affixed to the catheter tip 106 in a variety ofmanners, including solvent adhesion, sonic welding, co-extrusion, and soforth. Alternatively, the tip may be formed or extruded around thecontrol assembly, after which the entire tip structure may be affixed tothe jacket 114 or tube 112. In yet another embodiment, the catheter 100may be provided with a fluid-steerable armature.

FIG. 3 depicts a side view of the catheter 100 of FIG. 1. The braidedmaterial 118 incorporated into the catheter, outer jacket 114, adapter120, and electrodes 104 may be clearly seen. Further, because the tip106 is shown disassociated from the catheter shaft 110, a portion of thetube 112 and a trace 102 are also visible.

Generally, as shown in FIG. 3, the electrodes 104 formed on the surfaceof the catheter are relatively flush with the outer sidewall of thejacket 114. The electrodes 104 may extend slightly beyond the jacket 114surface, or alternatively may be slightly recessed, so long as the edgeformed by such extension or recession does not create a discontinuitybetween surfaces sufficient to abrade or damage tissue. The electrodes104 are generally formed on the jacket 114 surface, and are integral tothe catheter.

Still with respect to FIG. 3, the adapter 120 is shown without an outerjacket. An outer jacket may be placed around the adapter 120 to protectthe adapter traces 122 from damage, as well as to minimize electricalsignal noise or degradation resulting from electrical currents in tissueadjacent to the catheter. Generally, the diameter of the adapter 120plus the adapter jacket is approximately equal to the catheter 100diameter.

FIG. 4 depicts a cross-sectional view of a portion of the presentembodiment, taken along line A-A of FIG. 3. As mentioned with respect toFIG. 1, the present catheter 100 has a bitumen tube 112. Generally, thetube 112 may extend only partially along the length of the catheter 100.An inner layer 400, as shown, may extend along a portion of the catheterinterior. When fully assembled, the tube 112 may abut the inner layer400. This inner layer 400 may be a separate, adjacent tube, for example.The combination of inner layer 400 and tube 112 defines a passagethroughout the length of the catheter 100. When a tube having multiplelumens 116 is employed, as with the embodiment shown in FIGS. 1 and 4,the meeting point between the inner layer and tube may define theseparation of a single passage (i.e., the inner layer interior) intomultiple passages (i.e., the tube interior).

Also generally, the inner layer 400 (if present) underlies the outerjacket 114, and may impart additional structural strength to thecatheter 100. The inner layer 400 may also create a stair-step profilein combination with the outer jacket 114, facilitating electricalconnection between adjacent elements of the catheter shaft 110. Thestair-step profile of the inner layer and outer jacket combination mayalso aid in resisting shear force applied to the catheter 100. Further,the combination of inner layer and outer jacket may provide convenientsupport and protection to traces 102 disposed therebetween duringoperation and manufacture of the device. (The manufacture of anembodiment is disclosed in further detail below, in the section entitled“Method of Manufacture.”) It should be noted that the inner layer 400 isentirely optional. Alternative embodiments may omit the inner layer andsimply extend the tube 112 along the length of the catheter.

Also depicted in FIG. 4 is the transition between an inner layer 400 andthe bitumen tubing 112. In an embodiment having a single lumen tube, nointernal divider 402 separating the lumens would be present. Similarly,in an embodiment having a solid core tube 200 with no lumen (as shown inFIG. 2, for example), no passage would be seen.

As shown in FIG. 4, the device's outer jacket 114 may be made ofmultiple, abutting elements 404, 406 instead of being made from a singlepiece. When the outer jacket 114 is made of multiple elements (i.e., issegmented), one or more outer jacket elements 406 may include braidedwire or nonconductive fiber 118, as discussed above and shown in FIG. 4.Generally, the transition point between two adjacent outer jacketelements 404, 406 is substantially smooth. In other words, very littleor no discontinuity between outer jacket elements 404, 406 is formed onthe catheter 100 or lead exterior when the elements are bonded to oneanother to form a contiguous jacket 114.

The inner layer 400 and tube 112, by contrast, may or may not abut oneanother in an assembled catheter 100 or lead. A slight gap between thetube 112 (or bi-lumen tubing, as shown in FIG. 4) and inner layer 400may be present in some embodiments. In alternative embodiments, theinner layer and tube may be closely toleranced to ensure the end wallsof each abut. It should also be noted that the inner layer 400 may bemade of multiple elements, in a manner similar to the outer jacket 114.

Further, although the terms “inner layer” 400 and “outer jacket” 114 areused, an alternative embodiment may employ a single jacket having astair-step portion corresponding to the positioning of the inner layeror may omit the inner layer entirely. Accordingly, a single-jacketdesign may be used in some embodiments of the present invention.

In yet another alternative, and as also shown in FIG. 4, an outer jacket114 having internally formed traces 102 a may be paired with a tube 112or lumen having externally formed traces 102 b. Essentially, multiplefragmentary traces may be created, each running longitudinally along aportion of the catheter. In order to maintain an unbroken electricalconnection, each fragmentary trace 102 a, 102 b typically at leastpartially overlaps an adjacent fragmentary trace. Generally, andstarting at the proximal end, a jacket trace 102 a may be connected witha tube trace 102 b, which in turn is operably connected to an electrode104 through a via. Accordingly, the trace 102 may be formed anywherewithin the tube 112, thus imparting a greater degree of freedom inplacing the trace.

Similarly, where multiple tubes 112 or jackets 114 are employed, eachlongitudinally adjacent tube or jacket may have a trace 102 formedthereon. These traces may abut one another within the catheter 100,providing a contiguous path for transmission of electrical energy.

In the embodiment of FIG. 4, a first fragmentary trace 102 a is formedbetween the inner layer 400 and a first outer jacket segment 406.Generally, this trace 102 a may be formed along the interior sidewall ofthe first outer jacket segment 406, the exterior sidewall of the innerlayer 400, embedded within either jacket, or may be a multi-part tracepartially formed on the inner layer and partially on the outer jacket. Amethod for forming traces 102 is discussed in more detail below.

In addition to the first fragmentary trace 102 a underlying or formedwithin the outer jacket 114, a second fragmentary trace 102 b extendsalong the tube 112. As with the first fragmentary trace 102 a, thesecond fragmentary trace 102 b may be formed on the interior sidewall ofthe second jacket segment 404, within the jacket, within the tube 112,along the exterior sidewall of the tube, or on any combination of theabove. Essentially, the second fragmentary trace 102 b may be formedanywhere that permits it to electrically contact the first fragmentarytrace 102 a.

FIG. 5 depicts a cross-sectional view of a portion of the catheter 100and adapter 120 taken along line B-B of FIG. 3. In this cross-section,the adapter 120 includes the optional outer jacket 500 previouslymentioned, as well as an adapter inner layer 502. As with FIG. 4, FIG. 5shows the first fragmentary trace 102 a running along the first outerjacket segment 406. Here, however, the first fragmentary trace 102 aterminates at or near a portion of the adapter 120 having an adaptertrace 122. Generally, the adapter includes multiple adapter traces 122spaced along its circumference (or, in the case of a non-circularadapter, its edges). The adapter trace 122 electrically contacts thefirst fragmentary trace 102 a, completing an electric current path froman electrode 104 (not shown) on the catheter shaft 110, along the secondfragmentary trace 102 b (not shown), through the first fragmentary trace102 a, and along the adapter trace 122 to a connector (not shown) for adiagnostic or ablative apparatus.

As also shown in FIG. 5, the inner layer 400 typically terminates closerto the distal end of the catheter 100 than does the outer jacket segment406. The resulting shoulder 504 formed by the inner layer 400 and outerjacket 114 terminates movement of the adapter 120 into the interior ofthe catheter beyond the shoulder, thus facilitating properly positioningthe adapter trace 122 for longitudinal alignment with the catheter trace102 a. Of course, this stair-step configuration 504 may be formed inreverse, with the inner layer 400 terminating closer to the proximal endof the catheter than the outer jacket 114, and achieve similar results.

Although not shown, an alternative embodiment may include a groove orslot in either the catheter 100 or adapter 120 and a matching fin orextension in the other element. By aligning the fin with the groove, theadapter 120 and catheter 100 may be properly laterally aligned forelectrical connection of a catheter trace 102 to an adapter trace 122.In yet another embodiment, markings along the outside of the catheterand/or adapter may serve the same purpose.

2. Embodiment Having Multiple Inner Layers

In addition to the embodiments described above, another embodiment of acatheter 600 may have multiple inner, concentric layers nested within orbeneath the jacket 114. For example, a single catheter 600 may have anouter jacket 114, an outer tube 602, and an inner tube 604, as shown ina partially-exploded view in FIG. 6. Each layer (jacket, outer tube, andinner tube) may include a different type of electrically conductiveelement or may include electrically conductive elements in differentalignments.

For example, the outer jacket 114 may have one or more electrodes 104positioned along and extending through its outer sidewall, the outertube 602 may have one or more traces 102 operably connected to suchelectrodes 104, and the inner tube 604 (also referred to as a “lumentube”) may have yet another trace or traces 102 operably connected todifferent electrodes 104. In an embodiment including a tip electrode 108formed on the catheter tip 106, traces along or embedded within any orall of the aforementioned layers (i.e., jackets and/or tubes) mayconnect to the tip electrode 108.

Since the jacket 114 and tubes 602, 604 are typically made ofnonconductive material, traces 102 may run along or within each layerwithout electrically contacting one another, so long as a first tracedoes not run along an exterior sidewall of a first layer and a secondtrace run along an interior sidewall of an adjacent, concentric secondlayer. Longitudinally aligning traces 102 in this manner may beadvantageous where multiple contact points or electrodes 104 arelongitudinally aligned along the catheter surface. By separatinglongitudinally aligned traces with a layer of nonconductive material orplacing such traces in different layers 114, 602, 604, each electrode104 in the aforementioned alignment may be in electrical contact with atrace 102, without disrupting signals passing through another trace.

As with the embodiment of FIG. 1, any tip type or type of tube disclosedherein may be used with the embodiment of FIG. 6.

FIG. 7 depicts a side view of the catheter 600 of FIG. 6, showing theouter jacket 114, outer tube 602, and inner tube 604.

FIGS. 8 and 9 depict cross-sectional views of the present embodiment 600taken along lines C-C and D-D, respectively, of FIG. 7. Generally, theseviews are similar to those shown in FIGS. 4 and 5, but depict incross-section both the inner tube 604 and outer tube 602 of the presentembodiment, as well as multiple traces 102 c, 102 d longitudinallyaligned with one another. For example, FIG. 8 depicts a first trace 102c, initially positioned between the outer jacket 114 and outer tube 602,and a second trace 102 d, initially positioned between the outer tubeand inner tube 604. In this instance “initially positioned” refers tothe position of the trace with reference to the leftmost portion of thefigure, i.e., towards the distal end of the catheter 100. The first andsecond traces 102 c, 102 d each may be made up of multiple tracefragments, as discussed above in more detail with respect to FIG. 4.

As with the embodiment of FIG. 4, the outer jacket 114 of the presentembodiment 600 may be made of multiple outer jacket segments 404, 406.These segments may be bonded to one another, or may each be bonded tothe layer directly beneath them. Further, braided material 118 may beincluded in an outer jacket segment 406.

Similar to the single-tube catheter 100 discussed with reference toFIGS. 1 through 4, the present embodiment 600 includes a shoulderconfiguration 606. Part of this shoulder 606 is formed by a first innerlayer 608, which abuts the first tube. Here, however, a second innerlayer 610 forms a second portion of the shoulder 606 for contact withthe inner tube 604 defining the lumen 116. This second shoulder portionis optional, but may provide additional security with respect toproperly seating a tube. Further, the second shoulder assists inproperly aligning any inner tube traces 102 d within the catheterassembly.

FIG. 9 depicts a cross-sectional view of a multi-layer adapter 900connected to the catheter 600. Multiple adapter traces 122 a, 122 b maybe longitudinally aligned between or within the various adapter layers(such as the adapter outer jacket 500, adapter first inner layer 902,and adapter second inner layer 904) while maintaining electricalseparation of the traces. Each adapter trace 122 a, 122 b generallyaligns with and connects to a catheter trace 102 c, 102 d. Generally,the multi-layer adapter 900 operates in the same manner as the standardadapter, discussed below.

3. Adapter

FIG. 10 depicts an isometric view of the adapter 900 mentioned in thediscussion of FIGS. 6-9. Generally, this adapter embodiment differs fromthe embodiment 500 shown in FIGS. 1-5 in that it includes dual layers oflongitudinally aligned adapter traces 122 a, 122 b. The mating of theadapter 900 with the catheter 600 was previously discussed with respectto FIGS. 1, 5, and 9. The adapter 900 is shown with an outer jacket 500.

Typically, the adapter outer jacket 500 is formed from a nonconductivematerial that may or may not be identical to the material used to formthe catheter shaft 110. The adapter traces 122 a, 122 b may be exposedon the plug portion 1000 of the adapter (i.e., the portion of theadapter fitting within the catheter). Typically, these traces areconcealed within the nonconductive catheter shaft 10 once the adapter900 is mated with the catheter 600. Further, the traces 122 a, 122 b aregenerally embedded within the nonconductive material of the adapterjacket 500 and adapter tail 1002. In FIG. 10, such embedded traces areshown in phantom on the adapter tail 1002. The plug portion 1000 isgenerally shaped to include one or more steps 1004 designed to abut theaforementioned jacket shoulder(s) within the catheter 600. At least aportion of each adapter trace 122 a, 122 b is exposed in order to permitthe adapter trace to mate with the corresponding catheter trace 102.Typically, the adapter traces are circumferentially aligned with thecatheter traces. The width and thickness of both adapter traces 122 a,122 b and catheter traces 102 may be tailored to ensure the maximumelectrical energy necessary for diagnosis or ablation may be deliveredto a target site without physically affecting any portion of thecatheter or adapter.

The adapter body 900 may transition from a cylindrical shape to a planarshape. The cylindrical portion (i.e., the adapter jacket 500 portion andplug portion 1000) matches the catheter shape, while the planarconnection structure 1002 (the “fan tail” shape shown in FIG. 10)facilitates connecting a diagnostic or other medical apparatus and acatheter trace through one or more connection points, such as holes 1006(as shown) or prongs. Further, the adapter tail 1002 may splitlaterally, along the longitudinal axis of the tail, to permit attachmentto an apparatus having connectors so aligned.

FIG. 11 depicts an alternative embodiment of an adapter 1100. In thisembodiment, the adapter 1100 lacks the planar structure, or fan tail1002, of the embodiment 900 shown in FIG. 10. Instead, the adaptertraces 122 terminate in conductive prongs 1102 extending rearwardly fromthe adapter. Further, unlike the adapter 900 of FIG. 10, the presentadapter 1100 has a reverse stair-step configuration 1104 at the enddesigned to mate with the catheter. Accordingly, rather than inserting aportion of the adapter into a catheter 100, the catheter is at leastpartially inserted into the adapter. This requires the distal end of thecatheter 100 to have a mating stair-step protrusion. The shoulder 1104inside the adapter 1100 longitudinally aligns the catheter with theadapter. It should be noted that either type of adapter (one having afan tail or cylindrical prong arrangement) may be used with eithercatheter mating configuration.

FIG. 12 depicts the adapter 1100 of FIG. 11, as viewed from the distalend. (i.e., the end mating with a catheter 100). As can be seen, theadapter 1100 may have multiple layers of traces 122 making up theconnection structure, each designed to mate with multiple layers oftraces 102 in the catheter. These multiple trace layers may be offset,as shown in FIG. 12, or aligned with one another without affecting theoperation of the catheter or adapter. Further, it should be noted thatthe adapter traces 122 are all shown as round in cross-section. In orderto expose the adapter traces 122, a portion of each trace is removedsuch that the remainder of the trace is flush with the inner sidewall ofthe outermost layer in which the trace is formed (i.e., the outer jacket500, adapter first inner layer 902 or adapter second inner layer 904).For example, adapter trace 1200 sits between the outer jacket 500 andadapter first inner layer 902. Accordingly, the adapter trace 1200 isflush with the inner sidewall of the outer jacket 500. The adapter trace1200 is fully circular in cross-section for its length between the outerjacket 500 and adapter first inner layer 902.

FIG. 13 depicts a cross-sectional view of the cylindrical adapter 1100,taken along line E-E of FIG. 12. Two adapter traces 122 c, 122 d areshown in fine diagonal shading; these traces extend along the body ofthe adapter and terminate in conductive prongs 1102 c, 1102 d. Theentirety of the trace/prong structures are diagonally shaded. Forcontrast, nonconductive material making up the various adapter layers500, 902, 904 is shown in broader shading. The shoulder formed by thestair-step configuration 1104 of the adapter sidewall may also be seen.The adapter outer jacket 500, first inner layer 902, and second innerlayer 904 may also be seen.

In the side view of FIG. 13, the adapter traces exposed on the innersidewall of each adapter layer are shown. For example, one set of traces122 e may be seen extending along the outer jacket's 500 inner sidewall.These traces are hidden by the sidewall of the adapter first inner layer902. Each of the adapter traces 122 generally terminates in a conductiveprong 1102.

An adapter may include color-coding along its connection structure(either fan-tail 1002 or cylindrical prong 1102), identifying each wireor adapter trace 122 operably connected to the structure. However,because the adapter 900, 1100 is designed to mate with a connectingcable (which, in turn, connects to an input or output of a medicaldevice), the pin-out or arrangement of the connection structuregenerally connects the appropriate catheter trace 102 to the appropriateinput or output without requiring the user to identify individualtraces. In alternative embodiments, the adapter may directly connectwith a medical device, thus eliminating the intermediate connectorcable.

Additionally, the “fan-tail” shape of the adapter 900 facilitatesincorporating an access port (not shown) to permit leads, instruments,steering mechanisms, and so forth to pass into the adapter, into thecatheter, and down the lumen 116 (if any) running the length of thecatheter. In this manner, such items may be easily inserted into thecatheter body without interfering with the adapter's operation. Handlemechanisms to control steering mechanisms, medical devices attached toleads or instruments, and so forth may be attached to the appropriateelement outside the adapter body.

4. Catheter Having Embedded Wires

FIG. 14 depicts yet another embodiment of the present invention, namelya catheter 1400 having embedded wires 1402 in lieu of traces 102. Wiresmay be formed or embedded along the catheter when significant amounts ofelectrical energy must be delivered between an attached apparatus and anelectrical contact point on the catheter surface. One such applicationthat may require the use of a conductive wire 1402 instead of a trace102 is tissue ablation. The general physical structure of the catheterlayers (i.e., the outer jacket 114, outer tube 602, and inner tube 604)is similar to the catheter 600 depicted in FIG. 6.

The catheter 1400 shown in FIG. 14 is partially exploded. Accordingly, awire 1402 connected to the tip electrode 108 may be seen. Illustrativeconnections 1404 between the catheter shaft 110 and adapter 900 are alsoshown. In one embodiment, these connections 1404 are soldered, andgenerally connect each adapter trace 122 to a corresponding wire 1402.Soldering may also be used in previously-discussed embodiment to securean adapter to a catheter and connect adapter traces to catheter traces.

Generally, the wire 1402 operates in much the same manner as theaforementioned trace. It serves as a conduit for electrical energybetween an electrode 104 and apparatus. The wire may be co-extruded withthe catheter 1400, or may be placed within a depression (not shown)formed on or in a catheter layer (i.e., jacket or tube). One or morewires 1402 may run any length of the catheter 1400, as necessary.Typically, the wires are sufficiently flexible to permit the catheter tobend and/or be steered by a control apparatus. FIG. 15 depicts a sideview of the catheter 1400 of FIG. 14.

FIGS. 16 and 17 depict cross sectional views of the catheter 1400, takenalong lines F-F and G-G of FIG. 15, respectively. The cross-sectionalview of the catheter 1400 shown in FIG. 16 generally shows a stair-stepconfiguration, as previously discussed with respect to FIG. 8. On thedistal side of the catheter 1400, this configuration is formed by theouter jacket segment 404, the outer tube 602, and the inner tube 604. Onthe proximal end, the configuration is formed by the first outer jacketsegment 406, first inner layer 608, and second inner layer 610.

As with traces 102, wires 1402 may be embedded within a nonconductiveportion of the catheter 1400 or may be formed on a surface (inner orouter) of any catheter layer. Similarly, and as shown in FIG. 16,multiple layers of longitudinally parallel and laterally aligned wires1402 a, 1402 b may be employed in a single catheter and shielded fromone another by intervening nonconductive material. Further, multiplewires may longitudinally overlap one another to create a continuouselectrical path. For example, one wire 1402 a may run between (or beco-extruded with, or sit in a depression formed on either) the secondouter jacket segment 404 and outer tube 602. A second wire 1402 c maysit between the first outer jacket segment 406 and first inner layer608. These wires 1402 a, 1402 c generally at least partially overlap oneanother to form an electrical path running the length of the catheter1400. The same may be true for wire segments 1402 b, 1402 d runningbetween the outer tube and inner tube and outer jacket and inner layer,respectively.

FIG. 17 depicts a cross-sectional view of the mating junction betweenthe catheter 1400 and adapter 900. Conceptually, this view is similar tothe one shown in FIG. 9, except that wires 1402 c, 1402 d have beensubstituted for traces 102 c, 102 d. These wires 1402 c, 1402 d matewith adapter traces 122 a, 122 b to continue the aforementionedelectrical path.

5. Lead Incorporating Embedded or Formed Traces or Wires

Any of the catheter embodiments described above may also function as adevice lead having integrated traces 102 or wires 1402 and externallyformed electrodes 104. One exemplary function for such a lead is toregulate tissue contraction (for example, the beating of a human heart)by providing regularly timed electrical impulses.

Generally, an embodiment of the present invention taking the form of alead has a solid inner core 200 or tube, insofar as few if any medicaldevices must pass through the lead itself. Alternative embodiments,however, may include a lumen 116 running the length of the lead. If sucha lumen 116 is present, it is generally closed at the distal end of thelead. For example, a closed-end lumen 116 may permit a stylette to runsubstantially the length of the lead, thus providing additional strengthand rigidity to the lead. Typically affixed to the lead is a pacemakeror other power source capable of providing electrical impulses at timedintervals. The lead may also incorporate a diagnostic electrode 108 ator near the tip 106, in order to monitor the bioelectric impulsesgenerated by the regulated tissue. In this manner, the lead mayincorporate both the energy delivery or tissue regulating and diagnosticfunctions described herein. If a diagnostic function is provided, adiscrete trace 102 generally operably connects each diagnostic electrode104 (whether located along the shaft 110 or at the tip 106) to adiagnostic apparatus.

Although such electrical impulses may be delivered through anysufficiently conductive portion of the lead surface operably connectedto a power source (such as a pacemaker), many leads are equipped with atip or distal electrode 108. The location of the distal electrode 108 atthe end of the lead provides a simplified contact point for ensuringthat the electrode is in contact with the tissue, insofar as a doctor orsurgeon must maneuver only the tip of the lead into contact. Inalternative embodiments, the tip electrode 108 may be omitted and anelectrode 104 located along the lead sheath 110 may be used to deliverelectrical impulses. The lead may be permanently implanted, or may beintended for temporary use by a patient. An adapter 900, 1100, such asthose described with respect to FIGS. 10 and 11, may also be provided tofacilitate connection between the tip electrode 108 and the power sourceand/or the diagnostic electrode 104 and the diagnostic apparatus.

6. Method of Manufacture

With respect to one embodiment of the present invention (for example,the embodiment shown in FIGS. 1-5), different portions of a catheter orlead (collectively, “device” 100) are separately manufactured, thenbonded together. Broadly, four separate portions are manufactured andbonded. In order from the distal to proximal ends of the device, theseare: the tip 106, the portion of the device shaft 110 extending from thetip to a braided portion of the shaft, (the “distal shaft section”), theportion of the shaft 110 having a braided wire or fiber 118 (the“braided shaft section”), and the adapter 900, 1100. It should be notedthat alternative embodiments may omit one or more of these sections. Forexample, an alternative embodiment may omit the braided shaft section,instead connecting the distal shaft section directly to the adapter 900,1100. Yet another alternative embodiment may omit the distal shaftsection, and instead bond the tip 106 directly to the braided shaftsection.

FIG. 18 a is a flowchart depicting a first method for manufacturing ashaft 110 and adapter 900, 1100 of a medical device 100 havingintegrated traces 102, wires 1402, and/or electrodes 104. Generally, themanufacturing process consists of three main sub-processes 1810, 1820,1830, each of which detail the manufacture of a specific catheter orlead component. These sub-processes may be performed in any order. Forexample, sub-process 1820, detailing the manufacture of a braided shaftsection, may be performed before or after sub-process 1810, whichdepicts the manufacture of the distal shaft section.

Sub-process 1810 generally describes one exemplary method formanufacturing the distal shaft section. For example, in the embodimentshown in FIG. 8, sub-process 1810 details the manufacture of the innertube 604, outer tube 602, and outer jacket 114 of the shaft 110, allextending between the tip 106 (not shown) and the braided portion 118 ofthe catheter. In other words, sub-process 1810 details the manufactureof those portions of the catheter shown in FIG. 6 to the left of thestair-step configuration, with the exception of the device tip 106.

First, in operation 1811, a layer of the shaft 110 is extruded.Generally, the innermost layer is extruded first. For example, in theembodiment shown in FIG. 6, the inner tube 604 may be extruded inoperation 1811. Typically, the various concentric layers of the catheter110 (i.e., tubes 112 and/or jacket 114 s) are extruded from anonconductive polymer material. The geometry of each layer is dictatedby the catheter shape, size, and function.

Next, in operation 1812, traces 102 and/or wires 1402 are placed on theexternal surface of the layer, as necessary. It should be noted thatoperation 1812 is entirely optional; a layer may include no conductivetraces 102 or wires 1402. As part of this operation, traces are formedin or on the layers, presuming the traces and/or wires are notco-extruded. The conductive traces 102 may be placed on a single layeror spread across multiple layers of nonconductive substrate. In eithercase, conductive material may be electro-deposited or sputtered on thenonconductive member, or built up and adhered by any otherconventionally known means.

Another manner of creating the conductive traces 102 is to creategrooves or depressions 126 in the nonconductive material forming a tube112 or jacket 114 and selectively deposit conductive material into thegrooves. These grooves 126 may be formed during the extrusion process,or may be carved out of the tube or jacket surface as a separateoperation. Either electro-deposition or sputtering may be used to placeconductive material within the groove.

In yet another example, conductive material may be uniformly placedaround a cylindrical substrate having grooves or depressions 126 wheretraces 102 are desired. Once the conductive material is placed, all suchmaterial projecting above the surface of the nonconductive substrate maybe removed through abrasion, leaving only the desired traces 102 flushwith the layer surface. Typically, this creates a trace 102 on the outersurface of the substrate.

Alternatively, instead of forming traces 102 though a depositionprocess, traces may be formed by uniformly coating the cylindricalsurface and then selectively removing conductive material from undesiredlocations either by application of chemicals or by vaporizing theconductive material with laser light. Multiple trace 102 layers may bebuilt up by alternating extrusion of additional nonconductive substrateover a conductive layer with extrusion of a conductive layer. Generally,however, the outermost jacket 114 of the catheter is made of anonconductive material.

If conductive traces 102 are not capable of carrying electrical energyin sufficient quantities to permit the catheter to operate as desired,fine gauge wire 1402 may be incorporated into the nonconductivesubstrate during the extrusion process. The wires may be attached to themandrel and fed off a spool under tension. The position of the wires1402 with respect to the mandrel may be maintained by the tension on thewires, the wire path at the extrusion die, and position of the extrudedmaterial. Alternatively, wires 1402 may be placed within theaforementioned grooves or depressions or placed between concentriclayers instead of being extruded with the substrate comprising eachlayer.

Regardless of the method by which the traces 102 or wires 1402 areformed or extruded, these electrically conductive elements are generallyintegrally formed with the catheter. That is, once formed, the trace orwire generally is not removable, but instead is relatively permanentlyaffixed within the catheter body.

Following operation 1812, in operation 1813 it is determined whetheradditional concentric inner layers of the distal shaft section will beformed. A distal shaft section may have multiple concentric layers.Continuing the reference to the embodiment of FIG. 6, the outer tube 602surrounds the inner tube 604, constitutes a separate “inner layer” forpurposes of this determination, and is extruded over the inner tube.Generally, an “inner layer” of the shaft refers to any layer of thecatheter or lead shaft except the outer jacket 114. If additional layersneed be extruded over existing layers, then operation 1811 is againperformed, and the next concentric layer is extruded. After operation1811, traces and/or wires are formed on the next concentric inner layer,if required. Typically, the process of extruding a concentric innerlayer over a previously-extruded inner layer also bonds the layerstogether.

If, however, additional layers are not required (either because only asingle layer is necessary or all layers have been extruded), the outerjacket 114 is extruded in operation 1814. Once the outer jacket isextruded, the distal shaft section is cut to the desired length.Generally, the outer jacket 114 is formed of the same nonconductivepolymer as the inner layers, and is extruded over the inner layers.However, alternative embodiments may manufacture the outer jacket 114from a different substance, such as a second nonconductive polymer.Further, the outer jacket may incorporate co-extruded traces 102 orwires 1402, or such wires/traces may be formed on the outer jacket inany of the manners described with respect to operation 1812.

In operation 1815, vias are formed through the distal shaft section. Theformation of vias at least partially exposes the traces 102 or wires1402, and provides a pathway to electrically connect the traces or wiresto an electrode 104. Typically, the location of the via is chosen tounderlie the eventual location of an electrode. The via generally takesthe form of a hole extending from the outer surface of the catheter 100to the conductive trace 102 buried within the catheter. A conductivefilament may be placed in the via to connect the electrode 104 to thetrace, or the trace may extend or be built up through the via. Once thevia is in place above the trace 102, the remainder of the via may befilled with conductive material to seal open portions. It should benoted that this operation may be skipped entirely, insofar as the distalshaft section may not include any electrodes 104.

In operation 1816, electrodes 104 are formed on the outer jacket 114 ofthe distal shaft section. As with the previous operation, this operationmay be omitted if electrodes are formed only on the device tip 106 andnot along any portion of the shaft 110. Generally, electrodes may beformed of a single or multiple types of metal, or any other suitableelectrically conductive element. If multiple metals are used, the innermetal of an electrode 104 is typically selected for its adhesion to thenonconductive substrate and the outer metal layer is selected forbiocompatibility. Exemplary biocompatible materials include gold andplatinum. Intermediate metals, if any, may be selected for appropriatecohesive and electrical properties. The electrode metals, takentogether, form an integrated electrode capable of faithfullytransmitting bio-electric current from target tissue to a diagnosticdevice attached to the catheter, or electrical energy from such a deviceto the electrode. Electrodes 104 may be formed by sputtering,electro-deposition, depositing of metal into a depression on thecatheter surface, and so forth. As with traces 102, depressions 126 maybe formed on the catheter surface to assist in placing and creating anelectrode.

As with the traces 102, above, the electrodes 104 or other energydelivery elements are typically integrally formed with the catheterbody, and are generally not removable therefrom.

Next, in operation 1817, the “stair-case” profile discussed in moredetail above is formed. Generally, this profile is formed by cutting,planing, grinding, or otherwise removing material from inner or outerlayers. More material is progressively removed from each layer.

Generally, the proximal end of any given portion of the catheter 100(distal shaft section, braided shaft section, adapter etc.) isconfigured so that the innermost layer extends beyond the outermostlayer, while the distal end of any given portion is configured inreverse. In other words, portions of the outer jacket 114 and outer tube602 (if any) are removed at the proximal end of the distal shaftsection, so that the innermost layer (in the example of FIG. 6, theinner tube 604) extends furthest at the proximal end. Conversely, theinner nonconductive tubes and/or inner layers of the distal end ofdistal shaft section may be cored in a stair-step configuration toexposing the traces. In this manner, the proximal end of one section(for example, the distal shaft section) fits within the distal end of anadjacent section (for example, the braided shaft section). Thistransition is shown generally in FIG. 6. Alternative embodiments mayreverse the stair-step configuration of the distal and proximal ends ofany given section. Any required internal components (for example,portions of a steering mechanism, a stylette, a lead, and so forth) mayalso be added in this operation.

Sub-process 1820 generally describes the manufacture of the braidedshaft section. For reference, the “braided shaft section” refers to aportion of the catheter or lead shaft 110 incorporating a braidedmaterial 118, as discussed in more detail above. Generally, the methodof manufacturing the braided shaft section is similar to the method ofmanufacturing the distal shaft section.

In operation 1821, a shaft layer of the braided shaft section isextruded. The first time this operation is executed, the extruded layeris the innermost tube 112 or lumen 116. As with operation 1811 ofsub-process 1810, the various concentric layers of the catheter (i.e.,tubes 112 and/or jackets 114) are extruded from a nonconductivematerial. The geometry of each layer is dictated by the catheter shape,size, and function. In an alternative embodiment, the braided material118 may be co-extruded with any shaft layer, as desired.

In operation 1822, traces 102 are formed on the surface of the layerextruded in 1821. Generally, this operation is performed in a mannersimilar to that of operation 1812. Any or all of the methods describedwith respect to operation 1811 or elsewhere herein for forming traces102 or wires 1402 (or co-extruding traces or wires) may be used in thisoperation.

Next, in operation 1823, it is determined whether additional innerlayers must be extruded. Again, an “inner layer” in this context refersto any layer of the braided shaft section except the outer jacket 114.If additional inner layers are required or desired, then operation 1821is again executed and the next concentric inner layer is extruded overthe most recently extruded inner layer.

If no additional inner layers are to be formed, then in operation 1824the braid 118 is applied. As previously mentioned, the braid 118 may bemade of a metal or nonconductive fiber. The braid is typically appliedto the braided shaft section and sits between the outermost “innerlayer” and the outer jacket 114. In alternative embodiments, the braid118 may be placed between two inner layers, multiple braids may be used,or the braid may be co-extruded with any inner layer or the outer jacket114. Further, in alternative embodiments, the braid may be placedbetween inner layers, instead of between the outermost “inner layer” andthe outer jacket. In an alternative embodiment employing co-extrudedbraided material 118, this operation is typically omitted.

Typically, the braid material 118 is chosen according to the torquecharacteristics and column strength desired for the finished catheter.The braid material may also be chosen to minimize electrical signalinterference, or “noise,” caused in the traces 102 or wires 1402 byexternal electrical signals generated, for example, by tissue. The braidmaterial 118 may be incorporated into any layer of the catheter duringextrusion, or may be added between or atop a tube 112 or jacket 114prior to final assembly. In one embodiment, this material takes the formof braided, criss-crossing wires.

Next, in operation 1825 the outer jacket 114 is extruded and cut tolength. This operation is similar to the process described with respectto operation 1814.

In operation 1826, vias are formed through the outer jacket 114 and anyinner layers, if necessary. Because the braided shaft section is locatedcloser to the proximal end of the catheter or lead when assembled, itmay not include electrodes 104 formed on its outer surface. In such acase, there is no need to form a via. If, however, one or more vias areformed, the process is generally the same as that described with respectto operation 1815.

In operation 1827, electrodes 104 may be formed on the exterior of thebraided shaft section (i.e., on the outer sidewall of the outer jacket114). Again, this operation may be omitted in some embodiments. Whenthis operation is executed, it may be performed in any of the mannersdescribed above with respect to operation 1816 of the distal shaftsection sub-process 1810. Any required internal components (for example,portions of a steering mechanism, a stylette, a lead, and so forth) mayalso be added in this operation.

Finally, the last operation of sub-process 1820 is executed. Inoperation 1828, the previously-discussed stair-step profile is formed inthe manner generally set forth with respect to operation 1817.

In sub-process 1830, the adapter 900, 1100 is formed. Although twodifferent types of adapter are disclosed herein, sub-process 1830generally sets forth the method for manufacturing either adapter.

Initially, in operation 1831, a layer of the adapter 900, 1100 isextruded in the manner described above with respect to operation 1811.Next, in operation 1832, traces are formed on the external (or, ifdesired, internal) surface of the extruded layer. Adapter traces 122 (orwires, in some embodiments) are formed in the manner discussed abovewith respect to the formation of catheter traces 102.

In operation 1833, it is determined if additional adapter layers 500,902, 904 are to be extruded. If so, then sub-process 1830 returns tooperation 1831 and another adapter layer is extruded.

Otherwise, operation 1834 is executed. In operation 1834, the outerjacket 500 of the adapter 900, 1100 is extruded and cut to theappropriate length. After extruding the outer jacket 500, vias areformed in operation 1835. It should be noted that not all adapters 900,1100 require vias. Accordingly, operation 1835 may be omitted whenmanufacturing some embodiments.

Finally, in operation 1836, the customary stair-step profile is createdon the adapter 900, 1100. For example, this operation may form the plugportion 1000 of an adapter. The process for creating a stair-stepprofile is generally discussed with respect to operation 1817. Anyrequired internal components (for example, portions of a steeringmechanism) may also be added in this operation.

After sub-processes 1810, 1820, 1830 are complete, the catheter tip 106is typically formed in operation 1840. Alternatively, the tip 106 may beformed during sub-process 1810. Generally, the tip may be formed byovermolding additional nonconductive material onto the end of the distalshaft section, by heat bonding the end of the distal shaft sectionclosed, by adding additional nonconductive material to close any openingat the end of the distal shaft section, by mechanically- orpressure-sealing closed the end of the distal shaft section, and soforth.

As previously mentioned, the catheter may include a tip electrode 108.As part of operation 1840, the tip electrode may be formed byconventional means, or alternatively by plating a metal electrode overmolded non-conductive tip shape. A conductive trace 102 may be connectedto the metal electrode through a via. If a tip electrode is notrequired, the molded tip assembly may be formed without the metalelectrode or conductive traces and bonded to the distal end of thecatheter. In either case, the molded tip shape may contain radiopaquematerial to enhance visualization during fluoroscopy.

In operation 1850, the various components manufactured during thesub-processes 1810, 1820, 1830, as well as the device tip 106, arebonded to one another. In general, the male stair-step portion of onesubcomponent is inserted into the female stair-step cavity of theadjacent subcomponent. Heat-, adhesive-, chemical-, pressure-, orsonic-bonding may all be used to bond a layer of one component to anadjacent, underlying or overlying layer of a second component.

For example and with reference to FIG. 8, the first outer jacket segment406 partially overlies the outer tube 602. In operation 1850, the firstouter jacket segment 406 may be bonded to the outer tube 602. Likewise,the first inner layer 608 may be bonded to the inner tube 604. Thisoperation may also bond elements to longitudinally adjacent elements,although this is not required. Continuing the example, the end of thefirst inner layer 608 may also be bonded to the end of the outer tube604 where the two abut.

Generally, since traces 102 in adjacent sections of the shaft 110 wereexposed in steps 1817 and 1828, when properly aligned the traces mayform a continuous electrical path. This process may be repeated ifmultiple tubes are nested within one another inside the catheter.Similarly, this is true of the connection between catheter traces 102and adapter traces 122.

An alternative method for joining adjacent tubes 112 and/or jacketsegments 404, 406, as well as corresponding conductive traces 102, is toheat bond the non-conductive tube portions, while simultaneously bondingthe conductive traces with solder paste. The solder paste may beselected to flow within a temperature range required to bond thenon-conductive layers. Optionally, a ring of non-conductive material(such as that used to form the tube 112 or jacket 114) may be placedbetween adjacent tubes to ensure electrical isolation of differentconductive traces 102 or wires 1402.

Finally, in operation 1860, any external components may be added. Forexample, a handle to operate a steering mechanism may be added in thisoperation, or a pacemaker attached to a lead running the length of thecatheter 100.

Although the above process 1800 and sub-processes 1810, 1820, 1830 havebeen described with particular operations set forth in a particularorder, several operations may be omitted or performed out of order. Forexample, a stair-case profile may be formed for the distal shaft sectionin operation 1817 prior to forming electrodes in operation 1816 or viain operation 1815. This is but a single example; other operations mayalso be rearranged without deviating from or impacting the method ofmanufacture set forth herein.

Although the above operations are listed in a given order, it should beunderstood that an embodiment of the present invention may bemanufactured by a method omitting some operations, adding others, and/orchanging the order in which operations are executed. For example,electrodes may be formed prior to or simultaneously with traces.Accordingly, the aforementioned operations are illustrative of themanner of manufacture of a single embodiment of the present invention,and should not be construed as limiting all embodiments or all possiblemethods of manufacture.

FIG. 18 b depicts a method for extruding a shaft. First, in operation1810 b, an electrode 104, via, and trace 102 (or wire 1402) are formedand linked to one another to provide an energy delivery or sensingstructure. Unlike the method of manufacture described above with respectto FIG. 18 a, in this method the energy delivery structure is formed ina skeletal state.

Next, in operation 1820 b, any internal components (i.e. stylette,instrument lead and so forth) are suspended in place beneath or withinthe skeletal energy delivery structure. In other words, the internalcomponents are placed relative to the energy delivery structure so thatthey will occupy the lumen 116 or center of the solid core 200 when theshaft 110 is formed.

In operation 1830 b, the shaft 110 is overmolded over the skeletalenergy delivery structure and/or internal components. As part of thisoperation, the distal and proximal ends of the shaft section may beovermolded to provide the stair-step configuration previously discussed.Finally, in step 1840 c, the shaft 110 is bonded to the adjacentcatheter 110 elements, generally the tip 106 and adapter 900, 1100. Ifnecessary, portions of the overmolded shaft 110 may be removed to exposethe electrode 104 or trace 102.

The aforementioned overmold process may generally be used to form anadapter as well. This process is generally the same as that describedwith respect to FIG. 18 b.

7. Arbitrarily Shaped Electrodes

FIG. 19 depicts a partially-exploded view of a catheter 1900 havingarbitrarily shaped electrodes 1902. In the present embodiment, severalarbitrarily-shaped electrodes are located on the catheter's 1900 tipportion 1904, and one along the sidewall of the catheter jacket 114. Theterm “arbitrarily shaped,” as used herein, refers to the fact that theelectrodes 1902 may be manufactured in any size and shape desired, andshould not be taken to imply that the shape and/or size of theelectrodes 1902 are random. Arbitrarily shaped electrodes as describedherein may be located at any point along the exterior sidewall of thecatheter jacket 114 of tip 1904.

Generally, the arbitrarily shaped electrodes 1902 may be used for eitherenergy delivery (i.e., ablation) or diagnostic purposes (i.e., mapping).As with prior embodiments, the electrodes 1902 are often mounted on thesidewall of the catheter jacket 114, which in turn is constructed ofnonconductive material. Arbitrarily-shaped electrodes 1902 may also beformed on the catheter tip 1904, as shown in FIG. 19. Conductors, suchas the embedded or formed traces 102 or wires 1402 (not shown)previously discussed, may conduct electricity between the electrode 1902and a medical device attached to the catheter's proximal end. Suchconnection may, for example, be facilitated by the adapters 900, 1100 ofFIGS. 10 and 11. A temperature monitor, such as the thermistor 124and/or thermocouple discussed above, may also be affixed to the tip1904. Neither a thermistor 124 nor thermocouple are depicted on FIG. 19.

In order to insulate the electrodes 1902 from one another and fromadjacent, non-corresponding traces 102, the tip 1904 assembly may beovermolded. Further, overmolding the tip 1904 assembly with respect tothe electrodes 1902 and/or conductive elements 102, 1402 providessupport to both the electrodes 1902 and conductive elements, minimizingthe possibility of damaging or breaking these elements. The overmoldingalso provides a generally smooth finish for the tip 1904, thusminimizing the possibility of inadvertently damaging tissue due to tipdiscontinuities.

In a first exemplary method for manufacturing the arbitrarily shapedelectrodes 1902, the electrodes may be shaped as desired from anysufficiently conductive, biocompatible material, such as platinum orgold. Fine wires 1402 (not shown) may be soldered to the base of eachelectrode 1902, and the electrode and wire assembly may be mounted on orin a solid, flexible nonconductive tube 112, such as any layer formingpart of the catheter 1900. Generally, the wires 1402 and electrodes 1902are fixed along such a tube 112 in positions corresponding to the finalplacement of the electrodes on the tip 1904 or catheter 1900 sidewall.The tube 112 (with mounted wires) may be overmolded with a nonconductivematerial. This overmolding generally forms the tip 1904 and/or jacket114. Excess material may be removed through cutting or abrasion to shapethe tip 1904 and expose the electrodes 1902. Presuming the overmoldingdoes not form a catheter jacket 114, the tube may then be placed withinsuch a jacket and bonded thereto.

In a second method for constructing the arbitrarily-shaped electrodes1902, the electrodes may be electro-deposited or sputtered intoarbitrarily-shaped holes or depressions 126 on the exterior of thejacket 114 or tip 1904. (It should be noted that the depression 126shown on FIG. 19 is somewhat exaggerated for clarity. In manyembodiments, the depression 126 may be completely or nearly completelyfilled by the electrode 1902, thus hiding the depression from sight.)Generally, this sputtering or depositing may completely fill thedepression 126, or may leave a portion of the depression empty to allowlater passage of a wire or via through the empty section in order toconnect the electrode 1902 to a trace 102, wire 1402, or otherconductive element. Alternatively, the depression 126 may extendcompletely through the tip 1904 or jacket 114, and the electrode 1902may similarly extend throughout the entirety of the tip 1904 or jacket114. Since such an electrode 1902 extends from the exterior to theinterior of the catheter 1900, a via may not be required.

Alternatively, wires 1402 may be run along the exterior of a tube 112,or within the lumen 116 of a tube. The tube 112 may then be overmoldedas previously described and affixed to a jacket 114, thus providing thefinished catheter 1900 with a through lumen 116.

If necessary, a portion of the jacket 114 may similarly be removed toexpose the trace 102. This may be required, for example, where thearbitrarily-shaped electrode 1902 is formed on the exterior jacket 114surface, while the trace 102 is formed on or in the tube 112 or jacketinterior. The trace 102 may then be electrically connected to thearbitrarily-shaped electrode 1902.

Similarly, conductive traces 112 may be electro-deposited or sputteredon the exterior of the jacket 114, or wire 1402 may be extruded throughthe jacket 114 or tube 112 sidewalls. Vias may be formed by removingportions of nonconductive sheath material sufficient to expose traces102 or wires 1402 and inserting a connector (such as a fine conductivewire) into the hole formed by removal. The via may then connect theaforementioned trace 102 or wire 1402 to an electrode 1902 of arbitraryshape and size.

Once an electric connection is established between the trace 102 and theelectrode 1902, the assembly may be overmolded as discussed above, andmaterial may be cut or abraded away to expose the electrodes 1902. Asalso previously mentioned, multiple tubes 112 may abut end-to-end inorder to form a continuous catheter 1900 body. In such a case, thedistal end of each trace 102 may be exposed by removing nonconductivematerial from either an upper or lower surface of the trace, permittingadjacent traces to mate as necessary. This process was more fullydiscussed with respect to FIG. 18. Nonconductive material may similarlybe removed expose a sufficient portion of the trace 102 in order topermit mating with an electrode 1902, an adapter 900, or directly to amedical device.

As with previously discussed embodiments, various steering mechanismsmay be employed with the present embodiment. For example, a wire guideassembly may be connected to the distal end of the catheter 1900, or afluid guide assembly may also be so connected.

8. CONCLUSION

As will be recognized by those skilled in the art from the foregoingdescription of embodiments of the invention, numerous variations on thedescribed embodiments may be made without departing from the spirit andscope of the invention. For example, the exact number of layers used toform a catheter may vary from embodiment to embodiment, as may thematerial and composition of the catheter. Further, while the presentinvention has been described in the context of specific embodiments andmethods of manufacture, such descriptions are by way of example and notlimitation. Accordingly, the proper scope of the present invention isspecified by the following claims and not by the preceding examples.

1. A method of manufacturing a medical device comprising: forming adevice body by extruding a first cylindrical body layer; extruding asecond cylindrical body layer; placing the second body layer within thefirst body layer; and bonding the second body layer to the first bodylayer; forming a first electrically conductive element on the devicebody; forming a first electrode on the device body; and operablyconnecting the first electrode and the first electrically conductiveelement.
 2. The method of claim 1, wherein the step of forming a firstelectrically conductive element on the device body comprisesco-extruding a first electrically conductive element within the devicebody.
 3. The method of claim 1, wherein the step of forming a firstelectrically conductive element on the device body compriseselectro-depositing a conductive material on a nonconductive portion ofthe device body.
 4. The method of claim 1, wherein the step of extrudingthe second cylindrical body layer comprises extruding the secondcylindrical body layer over the first cylindrical body layer.
 5. Themethod of claim 1, wherein the step of forming a first electrode on thedevice body comprises the steps of: forming a groove on at least aportion of the device body; depositing conductive material within thegroove in a shape of the first electrode; and in the event that aportion of the conductive material extends beyond an upper surface ofthe groove, removing the portion of conductive material.
 6. The methodof claim 5, wherein the step of forming a groove on at least a portionof the device body is performed simultaneously with the step of formingthe device body.
 7. The method of claim 1, wherein the step of forming afirst electrically conductive element on the device body comprises thesteps of: co-extruding electrically conductive material with the firstcylindrical body layer; and removing a portion of the first cylindricalbody layer to expose at least a portion of the electrically conductivematerial.
 8. The method of claim 1, wherein the step of forming a firstelectrically conductive element on the device body comprises: coating asurface of the device body with an electrically conductive material; andselectively removing at least a portion of the electrically conductivematerial from the device body.
 9. The method of claim 8, wherein thestep of selectively removing at least a portion of the electricallyconductive material from the device body comprises exposing at least aportion of the electrically conductive material to a chemical solvent.10. The method of claim 8, wherein the step of selectively removing atleast a portion of the electrically conductive material from the devicebody comprises vaporizing at least a portion of the electricallyconductive material with a laser.
 11. The method of claim 1, wherein thestep of forming a first electrically conductive element on the devicebody comprises extruding a conductive layer across at least a portion ofthe device body.
 12. The method claim 11, further comprising: extrudinga second device body longitudinally encasing the device body andextruded conductive layer; and extruding a second conductive layeracross at least a portion of the second device body.
 13. The method ofclaim 12, further comprising the steps of: forming a tip structure; andaffixing the tip structure to the device body.
 14. The method of claim13, wherein the step of forming a tip structure comprises: plating ametal electrode over a molded non-conductive tip shape; forming a via inthe tip shape; and electrically connecting a trace to the metalelectrode through the via.
 15. The method of claim 1, wherein the stepof forming a first electrically conductive element on the device bodycomprises: feeding wire from a spool to a mandrel under tension;positioning the wire with respect to an ultimate location along thedevice body means of the mandrel; and co-extruding the wire with thedevice body.
 16. The method of claim 1, wherein the step of forming afirst electrically conductive element on the device body comprises:forming a groove on an exterior surface of the device body; and placinga wire within the groove.
 17. The method of claim 1, further comprisingthe step of affixing an adaptor to a distal end of the device body. 18.The method of claim 17, wherein the step of affixing an adapter to adistal end of the device body comprises: aligning an adapter trace withthe first electrically conductive element with an adapter trace; andinserting a portion of the adapter into the distal end of the devicebody such that the adapter trace and electrically conductive element areoperably connected.